Archive for the 'Plants' Category

Sep 24 2017

Leaves Turned White

Published by under Plants

Wingstem leaves turning white. Why? (photo by Kate St. John)

Wingstem leaves turning white. Why? (photo by Kate St. John)

In July and August I noticed something I'd never seen before along the trails of western Pennsylvania -- scattered instances of leaves turning white.

The leaves had been green but now their tips or even whole branches were white. The plant below had advanced to the stage where some of the stems were completely white.

Leaves in distress: top is white, 31 July 2017 (photo by Kate St. John)

Leaves in distress: top is white, 31 July 2017 (photo by Kate St. John)

The condition is called chlorosis and it means the plant is not producing enough chlorophyll to look green.  Since chlorophyll uses sunlight to make food for the plant, it's a sign the plant is in distress.  But why?

Causes of chlorosis are wide-ranging.  Here's the list from Wikipedia, with my [notes] added:

  • a specific mineral deficiency in the soil, such as iron, magnesium or zinc
  • deficient nitrogen and/or proteins
  • a soil pH at which minerals become unavailable for absorption by the roots
  • poor drainage (waterlogged roots)  [Not likely in this case.]
  • damaged and/or compacted roots  [Not likely in this case.]
  • pesticides and particularly herbicides may cause chlorosis, both to target weeds and occasionally to the crop being treated.  [Not likely in this case due to location.]
  • exposure to sulphur dioxide [Possible in Pittsburgh but not likely in this case.]
  • ozone injury to sensitive plants [Not likely in this case.]
  • presence of any number of bacterial pathogens, for instance Pseudomonas syringae pv. tagetis that causes complete chlorosis on Asteraceae.

Interestingly, the plants I photographed are in the Aster Family (Asteraceae) and one of them has complete chlorosis.

Was the 2017 growing season especially bad for the bacteria mentioned above?  Or does chlorosis happen every year and I've just not noticed?

If you know more about this condition in the wild, please leave a comment.  I'm really curious!

 

(photos by Kate St. John)

 

2 responses so far

Sep 23 2017

Variety of Goldenrods

Published by under Plants

Goldenrod at Mount Dessert Island, Maine (photo by Kate St. John)

Goldenrod at Mount Dessert Island, Maine (photo by Kate St. John)

Any trip outdoors this month will find a lot of goldenrods in North America.  Here are just a few of the species I've photographed over the years.  All of them are different.

Can I tell you their names? No. Goldenrods are notoriously hard to identify.

Above, a beautiful bushy goldenrod at Acadia National Park in Maine.

Below, the classic goldenrod shape in Pittsburgh: a tall plant with narrow alternate leaves and a tassel of yellow flowers on top.  To identify it I'd need more information than the photo provides.  For instance:  Do the leaves have two or three prominent veins?  Are they toothed or entire?  Is the main stem smooth or downy or both?

Tall goldenrod with a tassel on top (photo by Kate St. John)

Tall goldenrod with a tassel on top (photo by Kate St. John)

 

In the photo below: An unusual goldenrod shape photographed in Pittsburgh. The plant reaches out horizontally with flowers perched in clusters on top of the stem. The leaves are long and narrow.  Perhaps it's blue-stemmed or wreath goldenrod.

Perhaps this is blue-stemmed or wreath goldenrod (photo by Kate St.John)

Perhaps this is blue-stemmed or wreath goldenrod (photo by Kate St.John)

 

This one is a stand-up spike of yellow flowers with egg-shaped alternate leaves, found in Pittsburgh.

A goldenrod at Cedar Creek in 2015 (photo by Kate St. John)

A compact, upright goldenrod at Cedar Creek Park (photo by Kate St. John)

 

Is this goldenrod the same species as the tall tassel above?  I don't know.

A tall and bushy goldenrod, Schenley Park (photo by Kate St. John)

A tall and bushy goldenrod, Schenley Park (photo by Kate St. John)

 

I've never seen white goldenrods in Pittsburgh. This spike of white flowers was photographed at Acadia National Park in Maine.

White goldenrod in Maine (photo by Kate St.John)

White goldenrod in Maine (photo by Kate St.John)

 

And finally, a ball-shaped flower cluster with long leaves, growing in a granite crack at Acadia National Park.

Goldenrod in a rock, Acdia National Park, Maine (photo by Kate St. John)

Goldenrod in a rock, Acdia National Park, Maine (photo by Kate St. John)

So much variety.  So many goldenrods.  And often so hard to identify.

 

(photos by Kate St.John)

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Sep 05 2017

Leaves in Distress

Published by under Plants

Leaves in distress: defoliant (photo by Kate St.John)

Leaves in distress: defoliant (photo by Kate St.John)

Early in June I noticed curled leaves on all the trees and bushes by a road in my neighborhood.  Though I suspected it was caused by herbicide I was puzzled that other plants were not brown and dead.  Why would someone use an herbicide that maimed but didn't kill?  I forgot about it until I saw a photo of soybeans that looked the same way.

This summer, farmers from Arkansas to Ohio and North Dakota have experienced crop loss from a new formulation of the herbicide dicamba.  Dicamba has been used for a long time but this spring Monsanto, BASF and DuPont reformulated it for use with new genetically engineered dicamba-resistant soybeans.

The problem is this:  If your neighbor plants the new soybeans your fields could be affected.   The new dicamba volatilizes (evaporates) from the soil and leaves where it's applied and drifts as much as half a mile causing crop loss and low yield in everything else including non-resistant soybeans, tomatoes, watermelons, grapes, pumpkins and other vegetables.

At first affected farmers were reluctant to report a problem caused by their neighbors but crop losses have been so severe -- up to 80% -- that Arkansas, Missouri and Tennessee placed restrictions on dicamba use this summer and many have asked EPA to reconsider its approval.

I'll never know if dicamba was used in my neighborhood but I know now that an herbicide can do this.

Leaves in distress in my neighborhood (photo by Kate St. John)

Leaves in distress in my neighborhood (photo by Kate St. John)

Meanwhile the leaves are still in distress.  I took these photos last week.

 

(photos by Kate St. John)

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Sep 03 2017

Velvet Red

Published by under Plants

Cardinal flower (photo by Kate St. John)

Cardinal flower (photo by Kate St. John)

Cardinal flower (Lobelia cardinalis) is such a deep red color that it looks like velvet.

From a distance you'll see this perennial along streambanks, in wet places and swamps. The plant is as much as four feet tall.

It blooms in late summer and early fall, just in time for migrating hummingbirds to sip its nectar on their way south.

 

(photo by Kate St. John)

2 responses so far

Aug 29 2017

Green Eggs On Nettle

Green eggs on stinging nettle leaves (photo by Kate St.John)

Green eggs on stinging nettle leaves (photo by Kate St.John)

Today, a quiz.

I found green eggs on stinging nettle on August 9 at Wolf Creek Narrows, Butler County, PA.

Are they eggs or something else?

And who laid them?

Post a comment with your answer.

I'll reveal their identity later today.

 

THE ANSWER:  29 August, 3:15pm
This was a tricky quiz because the structures really do look like eggs. I thought they were butterfly eggs but they are too smooth. The likely butterflies lay very wrinkled eggs.  For instance, click here to see the eggs of the small tortoiseshell butterfly.

Mary Ann Pike correctly identified the green "eggs" as nettle galls of (probably) Dasineura investita.  The galls are the plant's defenses against the larvae inside them.  The larvae are from midges so tiny that I can't find photographs of the adult insects though these three photos may give you an idea.

Caterpillars of the Sordid Hypena moth (Hypena sordidula) eat these galls.  Click here to see it.

 

(photo by Kate St. John)

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Aug 27 2017

Ironweed Up Close

Published by under Plants

Ironweed, closeup of one flower (photo by Kate St. John)

Ironweed, closeup of one flower (photo by Kate St. John)

Ironweed is one of my favorite August flowers but it's hard for me to photograph.  Its purple color doesn't ring true on my digital camera (too blue!) and the plant is so tall that I've never been able to replicate Chuck Tague's quintessential view of it, below.

Tall Ironweed (photo by Chuck Tague)

Tall Ironweed (photo by Chuck Tague)

In August ironweed is truly impressive.  At seven to ten feet tall it's topped by a corymb (flat-topped cluster) of 30 to 50 deep purple flowers made up of 5-lipped florets. Dark red stems support long, alternate, lance-shaped leaves that are rough to the touch.

You've probably seen ironweed from the highway as it's the only tall flower left standing in cow pastures.  Its stem is so tough that cows refuse to eat it, thus the ironweed name.  On foot you'll find it in ditches, moist meadows and along stream banks.

In Pennsylvania there are two native species -- tall ironweed (Vernonia gigantea) and New York ironweed (Vernonia noveboracensis) -- distinguished by their bracts and florets per flower:

  • Tall ironweed (gigantea) has blunt or short-pointed bracts and 13-30 florets.
  • New York ironweed (noveboracensis) has long thread-tipped bracts and more than 30 florets per flower.

When you're up close with ironweed you can count its florets.  My photo from Frick Park shows less than 30 so this would be tall ironweed.

Or maybe not!  Tall and New York ironweeds hybridize.

Tall ironweed is listed as endangered in New York state and invasive in Kentucky.  I wonder why.

 

(photo credits: close up by Kate St. John, corymb by Chuck Tague)

*A corymb is a flat-topped cluster.  An umbel is shaped like an umbrella, rounded on top.

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Aug 24 2017

A Trumpet For Hummingbirds

Published by under Plants

Trumpet creeper with an insect inside (photo by Kate St. John)

Trumpet creeper with an insect inside (photo by Kate St. John)

Though we haven't had many hummingbirds this year, Pittsburgh's trumpet creeper is waiting to attract them.

Trumpet vine or trumpet creeper (Campsis radicans) is a woody vine native to eastern North America.  It's so well adapted to the forest edge that it aggressively climbs up to 35 feet to reach the sun.

Its beauty and scent are attractive to gardeners but it requires ruthless pruning.  The Lady Bird Johnson Wildflower Center says, "To keep it in check, plant it near concrete or an area that you can mow; mowing down the suckers will discourage them."

The flower is specially shaped for pollination by ruby-throated hummingbirds, the only hummingbird in this plant's native range.  The tubes are large and the anthers held high. The insect above is too small to pollinate it.

Learn more in this video by the Capital Naturalist.

 

As a trumpet for hummingbirds, it's probably so fragrant because ruby-throats like its scent.  Remember: we learned this month that birds can smell.

 

(photo by Kate St. John; video by The Capital Naturalist on YouTube)

4 responses so far

Aug 20 2017

It’s Probably Mugwort

Published by under Plants

Mugwort leaves are white underneath (photo by Kate St. John)

Mugwort leaves are white underneath, June 2017 (photo by Kate St. John)

There's a tall plant in the Composite family (Asteraceae) that used to confuse me, especially in early summer. Here's a trick for identifying mugwort.  It's everywhere right now.

Mugwort or common wormwood (Artemisia vulgaris) is an aromatic perennial native to Europe, Asia, northern Africa and Alaska(!).  It may have been brought here for medicinal purposes, but it spreads easily along roadsides and waste places.  I'm surprised it's not on Pennsylvania's Invasives list.

In early summer when mugwort is knee high, it looks like chrysanthemums because its leaves are similar -- sharply lobed.  The trick for telling them apart is this:  Look under the leaf. The underside of a mugwort leaf is white (above).

Mugwort leaves (photo by Kate St.John)

Mugwort's lower leaves in August (photo by Kate St.John)

 

By late August mugwort is three to eight feet tall with insignificant green flowers clustered at the leaf joints and at the tips of the stems.  The leaves near the flowers look different. They're linear, not lobed.

Mugwort's insignificant flowerscluster on the stem (photo by Kate St. John)

Mugwort's insignificant flowerscluster on the stem (photo by Kate St. John)

But it isn't beautiful.

In August a mugwort patch looks tall and messy.

Mugwort looks messy where there's a lot of it in August (photo by Kate St. John)

Mugwort looks messy in August (photo by Kate St. John)

 

Wondering what it is?  Flip a leaf.  It's probably mugwort.

 

(photos by Kate St.John)

One response so far

Aug 13 2017

Primrose Moths

Primrose moths on a primrose, Allegheny County,PA, 6 Aug 2017 (photo by Kate St.John)

Primrose moths on a primrose, Allegheny County,PA, 6 Aug 2017 (photo by Kate St.John)

Last Sunday I found a crowd of pink and yellow moths head down in a common evening primrose.  Bob Machesney identified them as primrose moths (Schinia florida).

I should have guessed their name.

Moths are often named for their host plant and so are these. Primrose moth caterpillars eat evening primrose, biennial gaura and other members of the Evening-primrose family (Onagraceae).  In July and August the adult moths fly at night and spend the day resting on their host plants.  That's why there were so many on one flower.

Keep an eye out this month for beautiful pink moths on primrose and biennial gaura.  Here's a common evening primrose (Oenothera biennis) without a moth in it.

Common evening primrose (photo by Kate St. John)

Common evening primrose (photo by Kate St. John)

Click here to see biennial gaura whose flowers are actually quite small.

And here's what the primrose moth looks like in a museum, mounted to show all its features.  Amazingly its antennae are pink.

Primrose moth specimen, mounted (photo from Wikimedia Commons)

Primrose moth specimen, mounted (photo from Wikimedia Commons)

 

(primrose photos by Kate St. John. photo of mounted primrose moth from Wikimedia Commons; click on the image to see the original)

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Aug 12 2017

Gone To Seed

Published by under Plants

Wild Bergamot gone to seed, late July 2017 (photo by Kate St.John)

Wild Bergamot gone to seed, late July 2017 (photo by Kate St.John)

Is this a daisy-like green flower with six petals?

No.

The green "petals" are sepals. The two lavender and white tubes on the left provide a clue. The central disc used to hold the flowers.

This is wild bergamot (Monarda fistulosa).  When in bloom it looks like this.

Wild bergamot in bloom in 2016 (photo by Kate St.John)

Wild bergamot in bloom, early July 2016 (photo by Kate St.John)

Still don't recognize it?  Click here to see a flower bed full of Monarda fistulosa.

It's a challenge to identify flowers when they've gone to seed.

 

(photos by Kate St. John)

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